Gymnophobe: from the Greek words "Gym" and "Gymno" meaning 'nude' or 'naked', and 'phobe' meaning 'fear'.
A gymnophobe is therefore a person who has either a fear, hatred, dislike, or intolerance towards seeing a person naked in any context.
The term is much used in the nudist and naturist culture to describe a person who is actively against their approach to life such as getting a nudist club or beach forcibly closed down.

"What are you, a gymnophobe?" - a locker room incident when a person runs into a cubicle to get undressed in the presence of another person who is nude, who thus utters the phrase.